LU83492A1 - NEW METHOD FOR PROTECTING METAL IN METALLURGICAL CONTAINERS - Google Patents

Description

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Claiming the priority of the c? N- · £ 'rd -:'? ·) Rorrespondanie (s) deposited; ';) -: · __! À-Â_L% j_s ^ / Ji _: - I le__ÂLûLL_AliQ_ sous n ° 8 g M. ^ H% _ / jg rr> or> de ho kJb'î.lÀ ^ / _ C.2061 / 8007 "1 i" · METALLURGICAL RESEARCH CENTER -CENTRUM VOOR RESEARCH IN DE METALLURGIE,

Non-profit association - Vereniging zonder winstoogmerk, in Brussels (Belgium)

New process for protecting metal in metallurgical vessels.

The present invention relates to a new process for: protection of metal in metallurgical vessels.

ί. _ j By metallurgical vessels, we must understand, in the | context of the present invention, any kind of container intended to contain liquid metal, such as for example cast iron or steel.

Among these, we can cite among others the ordinary ingot molds in _; chute or source, the baskets and ingot molds for continuous casting, the 'different metallurgical pockets, converters, cast iron mixers, etc ...

The following description focuses on the more specific case ’·

of continuous casting of steel, but this is only by way of example, / the invention in fact relates to the protection of contained metals / V

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In the continuous casting process of steel, and especially in the case of the continuous casting of ingots of large sections, it is well known to cover the liquid upper surface of the steel during casting with a protective material , of suitable composition, generally a fine powder for the mold and a powdery or granular material for the other containers.

The role of such a material being in the form of powder is multiple, in particular ensuring with respect to air a good thermal insulation of the upper surface of the ingot, protecting this surface against oxidation, capturing the inclusions present in steel and, for static or continuous casting molds, serve as a lubricant between the metal and the wall of the container.

The powders mentioned above can be prepared in many ways, in particular by making synthetic mixtures of various pre-ground components or by melting the various components of the powder together and then grinding the molten mixture thus obtained, after having cooled it. ''

Whatever the qualities presented by these powders, from the point of view of their particle size composition and their effectiveness relative to the lubrication of the ingot mold and to the protection of the metal, they nevertheless have a certain number of drawbacks 1 inherent in their very nature as powder.

. Among these disadvantages, we can cite: - the existence of fines, which are likely to be lost, from the j% stage of manufacture to that of use and which are in; besides a factor of unsanitary work; i "; c - the transport of the powders which, by segregation, necessarily causes an alteration in the homogeneity of their composition.

In order to avoid the serious defects mentioned above, the applicant has developed processes aimed at obtaining new products /

jj intended for the protection of liquid metal. These products were all / J

- 3 r η produced from the molten state of a mixture in defined proportions of the constituents of the powder considered. Subsequent research has made it possible to develop a process which has the advantage not. negligible to avoid the operation of melting the above-mentioned mixture before it is put into practical use form.

The subject of the present invention is a method by which it is possible not only to avoid the drawbacks mentioned above, but also to provide protection and thermal insulation of the metal in the containers, - in a particularly advantageous, easy and effective manner.

• The process which is the subject of the present invention essentially consists in carrying out a mixture in defined proportions of the various constituents of the powder in question, a mixture which is subjected to a determined treatment with a view to giving the above-mentioned mixture one or more defined forms.

In a first operational modality of the above process, the placing in the form or forms takes place in the pasty state.

According to another method of implementing the process, the preparation of the mixture involves one or more heating and / or cooling operations.

According to another mode of application of the method of the invention, the mixture undergoes grinding, in order to have predefined physical characteristics.

In a preferred variant, a binder is incorporated into the above mixture before it is shaped.

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According to a fifth method of implementing the method of the invention, the shaping has the effect of allowing the use of the aforementioned mixture in the form of a paste to be deposited on the metal to be protected / and / or of fibers and / or granules and / or ribbons and / or platelets, nj i '! 4 * · \

According to another variant in the application of the process of the invention, 'the product obtained after the above-mentioned mixture has been formed is subjected to a heat treatment, possibly a partial melting, before its practical use.

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This heat treatment operation has the advantage of making it possible on the one hand to remove certain gases such as CC ^, on the other hand to dry the materials obtained and finally in the case of partial melting,; to carry out a partial or total sintering of the product obtained.

The processing of the material thus prepared can be carried out in a discrete or continuous manner, automatic or not, by making use of the said material, either in the form of a continuous ribbon (whatever the shape of the section), or in form of distinct elements which, especially in the case of malleable dough, promote the joining in situ · in a single mass thereof, as it is deposited on the metal in the metallurgical container or on the layer of material already there. The deposit can be carried out from a single supply or from several, if the upper surface of the container · to be filled is large.

It is not beyond the scope of the invention to make the materials which are the subject of the pro- vacuolar or porous during manufacture! assigned above described. Such an operation can be carried out by inoculation in the fluid or pasty material of a suitable gas or of a material giving off a suitable gas, for example by evolution or hot gas decomposition, coming from the constituents of »· i; mixture or agents used as binders.

*. Said materials can also be obtained molded, - drawn, spun, extruded, etc., or in a form having one or more depressions of any configuration. This variant makes it possible to increase the thermal insulating power of said material, especially when it is in the pasty state. /? /! # t 5

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It is not outside the scope of the invention to use a mixture of these materials, either because they have the same shape, or because they have different shapes. One can also use in addition to one or more fibrous, granular or other materials, such as par. example of carbon, of boron nitride, used with or without a binder, and in proportions usually not exceeding 20% by weight of the total mixture. fj '' f i

Claims (11)

1. New process for protecting metal in ta - containers. metallurgical, characterized in that it consists in effecting a mixture in defined proportions of the various constituents of a protective material, mixture which is subjected to a determined treatment with a view to giving the above-mentioned mixture one or more defined forms. 2. Method according to claim 1, characterized in that the placing in the defined form or forms takes place in the pasty state. 3. Method according to claims 1 or 2, characterized in that the preparation of the mixture involves one or more heating and / or cooling operations. 4. Method according to one or more of claims 1 to 3, characterized in that the mixture undergoes grinding in order to present I predefined physical characteristics. 5. Method according to one or more of claims 1 to 4, characterized in that a binder is incorporated into the above mixture before it is formed. i * 6. Method according to one or more of claims 1 to 5, characterized in that the shaping has the effect of allowing the use of the aforementioned mixture in the form of a paste to be deposited on the metal to be protected and / or of fibers. and / or granules and / or ribbons and / or platelets. 7. Method according to one or more of claims 1 to 6, characterized in that the product obtained after the shaping of the above-mentioned mixture is subjected to a heat treatment, possibly a melting / partial, before its practical use. j V / Ύ. - <4 I 7! * * * 8. Method according to one or more of claims 1 to 7, characterized in that the said materials are made porous or porous during manufacture, for example by inoculation of an appropriate gas, or of a material giving off an appropriate gas. AT 9. Method according to one or more of claims 1 to 8, characterized in that the materials are produced in a form having one or more recesses of any configuration. 10. Deposition process on or above the metal found. in the mold for materials obtained according to either of claims 1 to 9, characterized in that this deposition is preferably carried out from several power sources, simultaneously and automatically. '' 11. Method according to one or more of claims 1 to 10, characterized in that the mixture of said materials also contains one or more components, in a fibrous or granular state, or other, such as carbon and / or nitride of boron, used with or without a binder and in proportions most often not exceeding 20% by weight of the total mixture. /. Drawings: -Z -— plates ^ pages of which .......... guard pin. Description of description. 2. Dv ^ r-s of claim _ZL ...... descriptive abstract 'Luxembovrc, te Charles München | ί *! j.